What is noise?
Also referred to as grain, noise is a visual distortion that shows up as speckles or dots of false colour on a photograph.
Noise is most likely to be an issue that affects picture quality when shooting in low light conditions. Darker areas of a photo and those of uniform colour such as the sky are usually where noise is most notable.
Picture quality plays a big part in what makes a mobile camera photo look good. Although these artefacts in film photography can sometimes be seen as a desirable effect that adds some character to a photo, more often than not, noise degrades the quality of a photo in digital photography.
ISO: 6400 | Shutter speed: 1/268s
What causes noise?
There are many factors that may contribute to the noticeable appearance of noise in photos. It may be as a result of one of the hardware-related issues below, a combination of some, or even all of them.
The image sensor is the key component of any digital camera, and in this case, size does matter. When it comes to smartphone cameras, this is one of the important phone camera specs you need to look out for.
In digital photography, the sensor is responsible for capturing light coming through the lens and converting the light information into an image we can appreciate.
The larger the sensor, the greater the potential it has to capture a lot more light than a smaller sensor would.
To be able to receive as much light as a large sensor would, a small sensor would need to electronically boost its light sensitivity. The greater the boost, the more the noise becomes apparent. More on this later.
Smartphone cameras are notorious for having very small sensors compared to other digital cameras such as DLRSs and mirrorless cameras.
Because of this, mobile cameras are more likely to take noisy photos under the same low light conditions as DSLRs.
Pixel size and density
It’s not just the size of the sensor that matters, but also the size of the photosites (for simplicity we’ll refer to them as pixels) and their density.
Pixels are found on the sensor and are what give a camera it’s megapixel count. These are light receptors that absorb light information coming from the lens, which the sensor then processes into an image.
The bigger the pixels are, the more light they can receive. Because of this, they have a high signal-to-noise ratio which means boosting the brightness of these pixels will not immediately result in noticeable noise in the picture.
Small pixels, on the other hand, capture less light which results in darker pictures. They have a low signal-to-noise ratio which means it doesn’t really take much to get noise in the picture when trying to increase the image’s brightness.
The size and density of the pixels is heavily dependent on the size of the image sensor. A large sensor can accommodate pixels of a larger size. If the sensor is small, so will the pixels be.
ISO controls the image sensor’s sensitivity to light. And while it may be necessary to turn it up when shooting in low light, it will at some point introduce noise in your photos. This is the boost mentioned earlier.
Generally speaking, the lower the ISO, the less likely you are to struggle with noise. Most often you’ll find the base ISO of a lot of smartphone cameras is set at 100.
How high up the ISO scale you can go before your picture starts looking noisy varies from device to device.
I advise you play around with this setting on your camera in different lighting conditions so that you can get a sense of how far you can push it before your picture starts looking too grainy.
How much noise is too much?
It’s really hard to say how much noise is too much and how much is acceptable because it really depends on what looks good to you. What I may think of as too much noise can be totally acceptable to someone else.
It also depends on what the photo is of and what you’re going to do with it. If fine detail in your photo is important, then you’d rather have as little noise as possible.
If you’re going to print your smartphone photos, the amount of noise in the photo can be a problem depending on the size of the print.
The bigger you print, the more likely noise will be visible. So you’ll need to reduce the noise as much as possible if you aim to print large images from your mobile phone.
What might appear as distracting noise in large prints might not be much of a problem on smaller printed photos.
How to avoid noise
Noise is an issue that can easily be dealt with. If the main problem is low lighting, then moving to an area where there’s adequate lighting might help with the noise issue.
Alternatively, try one of the solutions below.
Shoot at low ISO
As much as ISO is useful in brightening dark images, setting the value too high is what introduces noise in photographs. So the obvious fix would be to shoot at lower ISO settings.
ISO: 100 | Shutter speed: 1/17s
But won’t the photo look dark if the ISO is low? That may happen, therefore, you’ll need to slow down your mobile camera's shutter speed. This will keep the sensor activated long enough to collect more light.
To better understand how this works, I suggest you read about the Exposure Triangle here.
The downside is that your shots will be blurry if the camera moves even slightly, so you’ll need to keep your phone steady.
I highly recommend using a tripod or other camera support systems to help you with this. It’s honestly one of the best investments you’ll make because it will greatly improve your smartphone photography.
If you haven't already invested in a tripod, I suggest you go through these important points to consider that will help you get the right tripod for you and your phone.
Noise reduction in post
All the previous solution already discussed focus more on what to do to minimize noise before taking a photograph. But what about after the photo has been taken? Can the noise be corrected.
The simple answer is yes. There are a number of computer software available that can help you get remove noise from your photos.
An example of one such program is Adobe’s Lightroom. It has a simple slider that you can drag to reduce noise.
However, you need to pay a monthly subscription to use it. A free app you can try is Noise Reducer Pro, which is pretty decent itself.
You need to be careful, though, with noise reduction when editing. Too much of it can result in an obvious loss of detail in your image.
So as you perform noise reduction, keep an eye out on the overall appearance of your photo to avoid it having a somewhat plastic look.
Upgrade your phone
If all else fails and you’re still experiencing noise on your pictures, then the problem could be the quality of your phone’s camera.
If that’s the case, then you should perhaps consider buying a new camera phone with a better camera.
These three factors combined will certainly help minimize the amount of noise in your photos. It would also help if the phone has a pretty wide aperture.
Noise will forever be one of those things that photographers have to contend with. Unfortunately, there is not standard setting that will work on every photo. You just need to play around with the settings until you get a picture you’re happy with.
With more and more practice, dealing with noise will come naturally.
If noise is a big issue for you especially when taking photos in poor lighting, then check out my other article that discusses 8 ways you can improve the brightness of your photos in low-lighting without introducing noise.